Along with rapid development of the information technology, use of mobile terminals (such as mobile phone and tablet computer) becomes increasingly popular. Users have higher requirements on the mobile terminals. They not only require the mobile terminal to have a relatively high processing speed, but also increasingly rely upon WI-FI connection. Along with popularization of the mobile terminals and the WI-FI, the event of accessing a WI-FI network through a mobile terminal occurs more and more frequently.